1. Field of the Invention
The present invention relates to a rear wheel steering apparatus designed to control the steer angle of each of the right and left rear wheels of a vehicle on the basis of the turning condition of the vehicle, that is, in accordance with both the vehicle speed and the steer angle of front wheels of the vehicle.
2. Description of the Related Art
One type of rear wheel steering apparatus has already been proposed in which the steer angle of each of the right and left rear wheels is controlled by means of a hydraulic mechanism (see, e.g., Japanese Utility Model Laid-Open No. 192773/1983 and Japanese Patent Laid-Open No. 214470/1983). The arrangement of this prior art enables an appropriate cornering force to be generated during turning of the vehicle, thus allowing steering stability to be improved.
However, the rear wheel steering apparatus of the type described above suffers from the problem that the rise of cornering force is disadvantageously slow due to, for example, an unavoidable response lag in an electrical or mechanical control system, which involves unsatisfactory response to a change in the angle of steering rotation of the steering wheel, particularly when the vehicle is made to turn while running at high speed.